Re2: EnumMedia patch

[Maarten Lankhorst]

Robert Shearman wrote:
> Maarten Lankhorst wrote:
> > This patch fixes AM_MEDIA_TYPE->pbFormat not being handled correctly, 
> > unfortunately, this also means some stuff has to be rewritten to 
> > avoid memleaks, instead of CoTaskMemFree(AM_MEDIA_TYPE), 
> > DeleteMediaType has to be used.. This also fixes the errors i had 
> > with msn webcam, i feel like i stumbled over every bug in quartz 
> > now......
> >
> > @@ -45,6 +46,7 @@ void DeleteMediaType(AM_MEDIA_TYPE * pMe
> >         IUnknown_Release(pMediaType->pUnk);
> >         pMediaType->pUnk = NULL;
> >     }
> > - CoTaskMemFree(pMediaType);
> >
> > }
> >
> > BOOL CompareMediaTypes(const AM_MEDIA_TYPE * pmt1, const 
> > AM_MEDIA_TYPE * pmt2, BOOL bWildcards)
>
> This change is wrong. DeleteMediaType is not supposed to free the 
> memory used for the AM_MEDIA_TYPE structure itself as the function is 
> also used in places where the AM_MEDIA_TYPE was not allocated using 
> CoTaskMemAlloc.
>
> Rob

This change is right, if you don't want to release the format block you 
need to use freemediatype... quoting msdn...

*DeleteMediaType*

The **DeleteMediaType* *function deletes an allocated *AM_MEDIA_TYPE* 
http://msdn.microsoft.com/library/en-us/directshow/htm/am_media_typestructure.asp 
structure, including the format block.

*Syntax*

|*void WINAPI *DeleteMediaType*(
*    *AM_MEDIA_TYPE* /*pmt/
*);*
|

*Parameters*

/pmt /

Pointer to an *AM_MEDIA_TYPE* structure.

*Return Value*

No return value.

*Remarks*

Use this function to release any media type structure that was allocated 
using either *CoTaskMemAlloc* or *CreateMediaType* 
http://msdn.microsoft.com/library/en-us/directshow/htm/createmediatype.asp.

If you prefer not to link to the base class library, you can use the 
following code directly:

|void MyDeleteMediaType(AM_MEDIA_TYPE *pmt)
{
    if (pmt != NULL)
    {
        MyFreeMediaType(*pmt); // See FreeMediaType for the implementation.
        CoTaskMemFree(pmt);
    }
}
|

*Requirements*

*  Header:* Declared in Mtype.h; include Streams.h.

*  Library:* Use Strmbase.lib (retail builds) or Strmbasd.lib (debug 
builds).